höjdmodellens

A höjdmodellens, or digital elevation model (DEM), is a digital representation of the terrain's surface, typically showing elevation. It is a fundamental data product in geographic information systems (GIS) and remote sensing. DEMs are created using various methods, including photogrammetry from aerial photographs, radar interferometry, and digital capture from existing maps.

The primary function of a DEM is to provide elevation data for a specific geographic area. This data can be used for a wide range of applications. In hydrology, DEMs are crucial for understanding water flow, analyzing watersheds, and predicting flood extents. Geologists use them to study landforms, analyze erosion patterns, and map geological features. Urban planners and engineers utilize DEMs for infrastructure development, such as designing roads, planning drainage systems, and assessing construction sites.

DEMs can exist in different forms. A Digital Terrain Model (DTM) represents the bare earth surface, excluding features like buildings and vegetation. In contrast, a Digital Surface Model (DSM) includes these above-ground objects, capturing the "first surface" encountered by a sensor. The resolution of a DEM, which refers to the size of the grid cells representing the terrain, significantly impacts its accuracy and the level of detail it can portray. Higher resolution DEMs offer more intricate detail but require more storage and processing power.